Huge amounts of sewage sludge produced globally is a substantial environmental threat and require rational handling. Application in agriculture is an economical and relatively simple method of sludge management, however, it is associated with restrictions regarding metals content. According to EU regulations, the total amounts of Cd, Cu, Cr, Pb, Ni, and Zn have to be analyzed by the AAS technique requiring effective destruction of the organic matrix. Currently used methods of sewage sludge digestion may be biased when applied without optimization. The aim of the presented work was to evaluate the efficiency of the organic substances destruction in either raw or stabilized sludge. Three mineralization procedures were evaluated, namely: (A)—drying and microwave digestion; (B)—ignition and microwave digestion; (C)—drying and conventional digestion. For matrix destruction, a mixture of concentrated HNO₃ and HCl (3:1 v/v) was used. Metals were determined by flame atomic absorption spectrometry (FAAS). No limits of metal concentration were overdrawn. Generally, the method (B) was the most effective. Results obtained for Cu, Cd, and Zn after digestion by method (A) and (B) were comparable. Methods (B) and (C) yield complete decomposition of the matrix. As result, the precision of measurement substantially increases.

The pollution of urban soils by metals is a global problem. Prolonged exposure of habitants who are in contact with metals retained in soil poses a health risk. This particularly applies to industrialized cities with developed transport networks. The aim of the study was to determine the content and spatial distribution of mobile metal fractions in soils of the city of Łódź and to identify their load and sources. Multivariate statistical analysis (principal component analysis (PCA), cluster analysis (CA)), combined with GIS, were used to make a comprehensive evaluation of the soil contamination. Hot-spots and differences between urban and suburban areas were also investigated. Metals were determined by atomic absorption spectrometry (AAS) after soil extraction with 1 mol L⁻¹ HCl. In most sites, the metal content changes in the following order: Zn > Pb > Cu > Ni > Cd. About one-third of the samples are considerably (or very highly) contaminated, (contamination factor, CF > 3) with Cu, Pb, or Zn. In almost 40% of the samples, contaminated soils were found (pollution load index, PLI > 1). All metals have a strong influence on the first principal component (PC1), whereas second principal component (PC2) is related to pH. Polluted soils are located in the downtown, in the south and east part of the city. The distribution of contamination coincides with the urban layout, low emission sources and former industrial areas of Łódź.

A low-temperature redetermination by X-ray crystallography of four phenoxyalkanoic acid herbicides, 4-chloro-2-methylphenoxyacetic acid (MCPA), rac-2-(4-chloro-2-methylphenoxy)propionic acid (MCPP), 2,4-dichlorophenoxyacetic acid (2,4-D), and 2,4-dichlorophenoxybutyric acid (2,4-DB), allowed the supramolecular structures of these compounds to be precisely described in terms of C⋯O/C–H⋯π interactions. The geometric parameters of the redetermined structures agree with those previously reported, but with improved precision.